As a gate driving circuit which drives a semiconductor switching element (hereinafter, referred to merely as switching element) as a power conversion semiconductor element, for example, the following gate driving circuit has been hitherto proposed. Specifically, in the conventional technique, in the case where a switching element is driven by a constant current source, a detection voltage Ve obtained from a gate current Ic flowing from the constant current source via a shunt resistor to the gate of the switching element and a resistance value Rout of the shunt resistor is compared to a reference voltage Vref of a reference power supply by an operational amplifier, and feedback control of the gate current Ic is performed such that Ve is always equal to Vref, thereby reducing variation of a constant current (e.g., see Patent Document 1 described below).